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vector

vector System Class

Class Precedence List:

vector, array, sequence, t

Description:

Any one-dimensional array is a vector .

The type vector is a subtype of type array; for all types x, (vector x) is the same as (array x (*)). The type (vector t), the type string, and the type bit-vector are disjoint subtypes of type vector.

Compound Type Specifier Kind:

Specializing.

Compound Type Specifier Syntax:

(vector [{element-type | *} [{size | *}]])

Compound Type Specifier Arguments:

size—a non-negative fixnum.

element-type—a type specifier .

Compound Type Specifier Description:

This denotes the set of specialized vectors whose element type and dimension match the specified values. Specifically:

If element-type is the symbol *, vectors are not excluded on the basis of their element type. Otherwise, only those vectors are included whose actual array element type is the result of upgrading element-type; see Section 15.1.2.1 (Array Upgrading).

If a size is specified, the set includes only those vectors whose only dimension is size. If the symbol * is specified instead of a size, the set is not restricted on the basis of dimension.

See Also:

Section 15.1.2.2 (Required Kinds of Specialized Arrays), Section 2.4.8.3 (Sharpsign Left Parenthesis), Section 22.1.3.7 (Printing Other Vectors), Section 2.4.8.12 (Sharpsign A)

Notes:

The type (vector e s) is equivalent to the type (array e (s)).

The type (vector bit) has the name bit-vector.

The union of all types (vector C), where C is any subtype of character, has the name string.

(vector *) refers to all vectors regardless of element type, (vector type-specifier) refers only to those vectors that can result from giving type-specifier as the :element-type argument to make-array.

Expanded Reference: vector​

The vector Type​

The vector type represents one-dimensional arrays. Strings, bit vectors, and general vectors are all subtypes of vector.

(typep (make-array 5) 'vector)
=> T

(typep "hello" 'vector)
=> T

(typep #*10110 'vector)
=> T

;; Multi-dimensional arrays are NOT vectors
(typep (make-array '(2 3)) 'vector)
=> NIL

Parameterized Vector Type​

The vector type specifier can be parameterized by element type and size.

;; Vector of any type with any size
(typep (vector 1 2 3) '(vector * *))
=> T

;; Vector of exactly 3 elements
(typep (vector 1 2 3) '(vector * 3))
=> T

(typep (vector 1 2 3) '(vector * 4))
=> NIL

Vectors Are Both Arrays and Sequences​

Vectors are the intersection of array and sequence -- they support both array operations (like aref) and sequence operations (like map, reduce, find).

(let ((v (vector 10 20 30 40 50)))
  (list (aref v 2)           ; array access
        (elt v 2)            ; sequence access
        (find 30 v)          ; sequence operation
        (reduce #'+ v)))     ; sequence operation
=> (30 30 30 150)

Type Relationships​

(subtypep 'vector 'array)
=> T
=> T

(subtypep 'string 'vector)
=> T
=> T

(subtypep 'bit-vector 'vector)
=> T
=> T